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GeoJournal 23.3 1 9 7 - 2 0 6
© 1991 (Mar) by Kluwer Academic Publishers
197
Morphotectonics of the Baikal Rift Valley, Eastern Siberia, USSR
Ufimtsev, G.F., Prof., USSR Academy of Science, Institute of the Earth's Crust, Lezmontovstr. 128, 664033 Irkutsk, USSR
ABSTRACT: The Baikal rift valley, the central segment of the Baikal rift zone located in southern East Siberia, consists of two large depressions separated by an interdepressional uplift. The thickness of the Neogene-Quaternary sediments filling in the depression amounts to 5 km (Logatchev and Florensov 1978). The interdepressional uplift consists of subsiding residual steps and active tilted horsts.
The NW slope of the Baikal rift is controlled by a system of faults diverging to the N. This system comprises tectonic scarps (faceted ridge spurs), an inclined piedmont surface and a summit slope. The facets indicate the position of the main dip slip faults behind which longitudinal strike slip faults are distributed. Between the branching faults, the so-called intermediate steps are situated. Their subsidence and destruction result in expansion of the rift valley. Transformation of normal faults into listric faults is manifested in the tectonic topography in the areas of the residual and intermediate steps. The large dimensions of the Baikal rift valley are evidently due to its being confined to the faults striking NE-SW.
Introduction
The Baikal rift valley is usually considered to be the central segment of the rift zone of the same name (Florensov 1960, 1969; Logatchev and Florensov 1978). This is the largest valley in southern East Siberia. The dimension of the basins forming the valley are twice the mean dimensions of the other rift valleys in the region. However , the symmetric structural features of the Baikal rift zone indicate that the Baikal rift occupies a common posi t ion and that its structure does not possess any ext raordinary features. This phenomenon should be taken into considerat ion when explaining the large dimensions of the Baikal rift valley.
The Baikal zone structure is well expressed in the transverse profiles crossing the Baikal rift zone in the lake region (Fig 1, 2). The rift zone includes: (1) asymmetric block uplifts at the N W wing, (2) the axial system of rift valleys and interdepress ional uplifts, (3) s tepped block uplifts between the rift valleys (Fig 2, I) or on their slopes (Fig 2, VI) a domal uplift at the SE wing.
On the slopes of the basins are dis tr ibuted large steps that are structurally connected with the in terdepress ional uplifts (Fig 2, IV). The rift zone structure is paragenet ical ly connected with the structure of the upwelling of the anomalous mantle reaching the Moho below Lake Baikal (Puzyrev 1981; Zor in 1981). The inclined horsts at the N W wing of the rift zone are located above the subvertical boundary of the anomalous mantle upwelling. A b o v e the welling, rift valleys and s tepped block uplifts are distr ibuted. The domal uplift on the SE flank of the rift zone is a topographic expression of the transit ion of the vertical anomalous mant le upwelling into its layer below the Moho discontinuity (Ufimtsev 1986). Large covers composed of Cenozoic basalts are also located there. This paragenesis of the morphotectonic features of the rift zone and its deep structure contr ibute to our knowledge of rifting. In addit ion, the analysis of morphotectonic features alone allows us to infer many characteristics of tectonogenesis in the subsurface levels of the l i thosphere where deformat ion of tectonic stress fields below the intricate mounta in relief takes place.
198 GeoJournal 2 3 , 3 / 1 9 9 1
The basins of the Baikal rift valley are compound structural elements. Their SE slopes are characterized by complex combinations of faults. The NW slopes of the basins consist of tectonic scarps up to 2000 m high (Fig 3, 4), forming an intricate system diverging to the NE. The entire system is named the Obruchev fault (Fig 1) (Lamakin 1955). Morphotectonic features of rifting, such as faceted mountain spurs and fault scarps, are distinctly expressed there.
t 04 o ~06 o r I J ~ .I ~ F" I ~
Fig 1 The Baikal rift valley and the surrounding morphotectonic elements. 1 - faults of Obruchev system, 2 - land rift valleys, 3 - inter-depressional uplifts, 4 - inclined horsts and asymmetric block uplifts of NW wing of rift zone (rift shoulders), 5 - stepped block uplifts, 6 - domal uplift of SE wing of rift zone, 7 - Siberian platform boundary. Scheme A shows position of Figures and their numbers. Scheme B shows major tectonic features of the rift valley; lines mark profiles crossing rift zone, cf. Fig 2.
The Baikal Rift Valley
The Baikal rift valley is a compound landform consisting of two deep basins (Fig 2, I, III , VI) that are separated from each other by a diagonal (NE-SW) interdepressional uplift which includes the uplifts of the Olkhon Island, Svyatoi Nos Peninsula and the underwater Akademichesky Ridge (Fig 2, II, III). Lake Baikal is 889 m deep in the N basin, and 1620 m deep at the most in the S basin. The avandelta (underwater portion of delta) of the Selenga river divides the South Baikal basin into two parts and covers rather small uplifts, e.g. the Posolskaya bank (Fig 2, V). The maximum thickness of the Cenozoic sediments (up to 5 km, according to geophysical data) are observed in the Selenga delta and the South Baikal basin (Zorin 1981). Sediments within these basins date from the Miocene to the Quaternary periods (Logatchev and Florensov 1978).
Interdepressional Uplift
Large steps appear in the places of major branching of the Obruchev fault. These steps occur between the basins and the asymmetric block uplifts of the Primorsaky and Baikal ridges which compose the NW rift shoulder (Fig 3). Along strike the largest step is changed into an uplift dividing the rift valley into individual basins. The branching within the Obruchev fault system is well manifested near the Buguldeika mouth (Fig 5), where the fault is divided into the Primorsky and Priolkhonsky faults limiting a large step (Fig 2, IV). To the NE this landform gives place to a complex interdepressional uplift which consists of the NW inclined uplift of the Olkhon island and the residual step adjoining the uplift in the NW (Fig 2, III; 6). On the SE, the Olkhon uplift is bounded by a high and steep tectonic scarp (Fig 7), half of which lies below the water level (Fig 2). According to C TM dating, local lake terraces on the scarp suggest that much of the uplift took place in the Late Pleistocene - Holocene period. The NW flank of the Olkhon uplift is an inclined surface (Fig 6, 7). In addition to the exposures of Precambrian rocks, rather small (up to 15 km 2) Neogene depressions are located on the surface. The depressions were uplifted and tilted by tectonic distortions in the Quaternary, The change from primary subsidence to further uplift is also inherent in the other interdepressional uplifts of the Baikal rift zone.
A narrow residual step strikes along the Olkhon uplift. In the NE part of the island (Fig 6) within the step at a height of 100 to 150 m above the level of lake, a Cretaceous-Paleogene weathering surface with a kaolinic weathering crust is exposed (Florensov 1974). Within the residual step, active abrasion of modern shores are distributed everywhere indicating slow subsidence of the island. On the NW shore of the island, the residual step is dissected by abrasion into several islands and semi- island blocks. In the SW part of the Maloye Morye strait separating the Olkhon island from the mainland a r i a coast is present within the residual step. This indicates that the residual step is still subsiding.
Northeast of the Olkhon island the interdepressional uplift forms the underwater Akademichesky ridge. Residual steps and active uplifts are also observed there. Within the residual steps, outcrops of the ancient curst of weathering are exposed (Goldyrev 1982), and the active uplift rises above the lake level (Ushkany Islands, Fig 2).
GeoJournal 2 3 . 3 / 1 9 9 1 1 9 9
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Cross sections of the Baikal rift zone and their structural interpretation (thin lines). Vertical scale is 10 times the horizontal.
Fig 3 The Baikal rift valley slope near the Muzhinai cape. The Burgunda mountain massif being a part of the rift shoulder (left and centre) and the large Tuya-Kotelnikovo step (right). View from the south. _ _
Fig 4 The slope of the South Baikal basin near the Maritui village. The uplifted marginal part of the Siberian platform is the rift shoulder. It is cut by the Obruchev fault. View from the south.
7 % 5 ~ . ~ - : ~ - : ---~-~ ,4/ i ~ ~ ._-~.-- =~
200 GeoJournal 23.3/1991
Fig 5 The mouth of the Buguldeika river where the Obruchev fault diverges. The intermediate step on the valley slope is separated from uplift by the scarp of the Primorsky fault.
Fig 6 Northern segment of the Olkhon island (view from the NW). A low residual step with fragments of Cretaceous-Paleogene peneplain (left) frames the inversional Olkhon uplift (right and centre). The NW termination of the Zunduk intermediate step (shown in the right foreground).
On the latter, tectonically distorted lacustrine terraces are distributed. The areas of active uplifts in the underwater part of the interdepress!onal uplift are similar in their morphology to the Olkhon uplift.
The interdepressional uplift between the S and N basins of Lake Baikal is a typical example of such structural forms which are very significant in the structure of the rift zone. These structural forms include small basins, horsts and residual steps whose destruction results in the expansion of intermontane basins.
Fig 7 Tectonic scarp limiting the Olkhon uplift on the SE. A tectonic distortion within the uplift tell us where it is.
The Rift Valley Slope
The NW slope of the Baikal rift valley is a geomorphic expression of the faults of the Obruchev fault system. The slope is a combination of the following elements: (1) system of steep triangular basal facets, (2) inclined piedmont plains, usually accumulative (system of fans), (3) systems of inclined spurs above basal facets (summit slopes), and (4) intermediate steps (Fig 8). The significance of the above elements in the morphology of the rift valley slopes is varied. Systems of facets are their common central elements (Fig 3, 4, 7, 9, 10, 11). They are absent only in rare cases, one of which will be considered further in the paper.
The system of steep facets are aligned with the major active normal faults bordering the rift valley. These triangular and trapeziform slopes are generally steeper than 30 ° and range in height from a few tens of metres to many hundreds of metres. The active faults along with which these facets occur are normal faults dippings at angles of 60 to 80 ° towards the rift valley. Simple facets (Fig 3, 4, 9, 10) and their complex combinations (Logatchev 1987) are frequent. At the base of the tectonic scarps, rather low basal facets (Fig 11) are present with narrow (tens of metres) steps located above them. Above the latter steps, high summit facets are
GeoJoumal 23.3/1991 201
./"-''h
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J "//-"// ; ~~k_ Fig 8 Cross sections of the Primorsky ridge showing the
structure of the NW rift valley slope. 1 - tectonic scarp (system of steep fault facets), 2 - summit slope, 3 - inclined piedmont plain, 4 - intermediate steps. Vertical scale is 10 times the horizontal.
/ , ; i~ ~ ~ ~ ; ~ m _ _
Fig 9 Tectonic scarp on the NW Baikal shore near the Goloustnaya river mouth.
commonly present. The subdivision into summit and basal facets may be due to one or more of the following reasons: (1) a hiatus in tectonic displacements along the marginal faults of the rift valley, (2) branching of fault surfaces, and (3) presence of faults with small magnitudes of displacement in the wide zone of the major fault. The lat ter cause is widely observed. Ra ther low basal facets (Fig 11) are observed at the base of the tectonic scarp on the N W shore of the Maloye Morye strait near the Zunduk river mouth (Fig 11). Their steep and straight surfaces strike along elongate planes of fissures dipping at angles of 40 to 50 ° towards the lake. Along these fissures, gravity sliding of lamellar blocks occurs. This results in re juvenat ion of basal facet surfaces, which remain steep, and in the format ion of the narrow steps above the basal facets. Gravi ty tectonics of the subsurface port ions of the l i thosphere is one of the evolut ionary characteristics of the tectonic scarps on the slopes of the Baikal rift valley.
Fig I0 Primorsky fault scarp near the Sarma river mouth. A system of steep fault facets, a summit slope above it and an inclined piedmont plain constitute the rift valley slope. Their roles in the slope structure are identical.
202 GeoJoumal 23.3/1991
7 "%
Fig 11 Tectonic scarp on the NW shore of the Maloye Morye strait near the Zunduk river mouth. Systems of basal and summit facets are visible. Arrows show scarps and conjugated trenches having paleoseismic origin and cutting debris cones.
The extensive distribution of gravity tectonics results from widely manifested late Pleistocene and Holocene tectonic displacements along the Obruchev fault.
Numerous, low (not exceeding 10 to 20 m) fault scarps are distributed at the foot of the larger, faceted tectonic scarps on the NW slope of the Baikal rift valley. They are accompanied by elongate grabens tfiat are 1.5 to 2.0 m deep. The graben-scarp systems cut the bases of the tectonic scarp facets of large debris cones. These are traces of young tectonic displacements and are usually considered to be the result of prehistoric earthquakes (Solonenko 1973). Such scarps are common along the tectonic escarpment of the NW slope of the rift valley (Fig 11).
Due to periodic tectonic movements and formation of graben-scarp systems at the base of the tectonic escarpments, gravity instability of rock massifs appear within the scarps. This leads to rocky landslides on the slopes' gently dipping tectonic zones. The rocks from the rift valley slopes are strongly fragmented. The results in
dangerous exogenic processes i.e. stone streams and seismic collapses.
The summit slope is located above the facet systems (Fig 8). The morphological features and significance of summit slopes in the structure of rift valley slopes are varied along their strikes. Sometimes summit slopes are absent (Fig 4, 9). In other cases they are represented by a system of steep crests over fault facets (Fig 3, 7). Summit slopes are well expressed in the middle segment of the Baikal rift valley, near the shore of the Maloye Morye strait (Fig 10) and to the SW (Fig 12), where they are expressed by systems of broad, inclined surfaces confined to the blastomylonitic zone of the Primorsky fault. In some places, the summit surfaces constitute a major part of the tectonic scarp. The basal fault facets are no more than 100 m high (Fig 12).
In the band of summit slopes, large valleys crossing them form horizontal knee-like curves. They have similar orientations and constitute conjugated systems along the strike of the rift slopes. The longitudinal translations of
Fig 12 Primorsky fault scarp near the Yelantsy village. Low basal facets and a wide summit slope above them are seen in this view to the N.
Fig 13 Strongly eroded intermediate step near the Pechanaya bay; view to the N.
E
GeoJoumal 23.3/1991 203
Fig 14 Shore slope in the region of the Sredny Kedrovy cape. The intermediate step is at the final evolutionary stage. At the bases of the fault facets and below there is an intricate system of scarps and trenches which represent traces of a strong pre-historic earthquake.
Fig 15 Northwestern shore of the Maloye Morye strait. The Zunduk intermediate step (foreground) and the uplift of the Primorsky ridge.
the knee-like valleys result t rom strike-slip faults: dextral faults are present on the NW rift slope whereas sinistral faults are present on the SE slope. The Baikal rift valley is moving southeasterly relative to the surrounding uplifts.
The summit slope morphological features and their relation with the blastomylonitic zones, as well as its conjugation with other tectonic landforms, suggest that the inclined summit slope surface was formed due to small-scale dislocations along several faults that are present behind the main frontal normal fault, that latter which is expressed as a system of steep facets.
The geological and morphological data allow us to recognize spatial relations between vertical and horizontal tectonic displacements on the slope of the rift valley. In the central segments of the slope, faults display primarily normal slip, whereas in the rear part of the rift valley
slope, small-scale normal faults and major strike slip faults prevail.
A gently sloping piedmont belt, usually comprised of alluvial fans, is the third element of the rift valley slopes (Fig 3, 5, 11, 12). Locally, the piedmont plain is a suballuvial bench or piedmont with bedrock outcrops exposed through the thin alluvial cover. The bedrock is usually dissected by numerous small amplitude faults, the zones of which are filled with unconsolidated (Recent?) tectonic breccias. In the zone of piedmont plains, as well as in the rear segment of the rift valley slopes, small- amplitude faults are distributed.
In some places, the inclined piedmont plains are pediments which replace intermediate steps at the final stages of their development (Fig 13). Two processes go on simultaneously: (1) denudational destruction of the intermediate steps, and (2) tectonic deformation of newly
Fig 16 Stepped slope of the Baikal ridge near the Rytuy cape replaced in the NE (right) by a system of fault facets. In the foreground the surface of a large debris cone is seen.
204 GeoJournal 23.3/1991
(.._ Fig 17 Shartla intermediate step which is a combination of a fault with a collapse. The scarp is 800 In high and over. This was initiated in no time geologically (Solonenko 1973). Arrow shows a fault scarp cutting a debris cone.
formed denudation plains which are not covered by piedmont sediments. Such a situation is observed in the Sredny Kedrovy cape area (Fig 14) with its known seismogenic dislocations (Florensov and Galkin 1967). Seismogenic grabens and scarps are distributed at the foot of fault facets and cut the upper part of the steep and high (over 500 m) inclined piedmont surface on which isolated mountains are located. In our opinion, these mountains are relics of a formerly existing, narrow, intermediate step. The latter was eroded and transformed into a piedmont denudation plain which experienced simultaneously tectonic deformations and is covered by piedmont sediments.
The tectonic scarps on the NW slope of the Baikal rift valley are divided into sections by transverse faults along which large valleys strike. This is well expressed at the step of the Primorsky fault on the NW shore of the Maloye Morye strait (Fig 15). Each section covers three or four facets joining together at their bases. They are separated from each other by large valleys. Large transverse faults cut the slope of the rift valley and the Primorsky ridge, along which stepped deformations of a preorogenic erosional surface are observed.
Intermediate Steps
Intermediate steps are another characteristic element of the Baikal rift valley slopes. These are narrow tectonic
blocks, with varied lengths, occupying an intermediate position on the rift valley slope between its base and the adjacent uplifts. The shapes and dimensions of the intermediate steps on the NW slope of the rift valley are diverse (Fig 5, 13, 14, 15, 16, 17). They are localized within the wide zone of the marginal fault. The intermediate steps are usually distributed between the diverging branches of the main fault. The rift slope becomes stepped when the fault branches are numerous (Fig 16). Perhaps, individual small steps were formed within very short geological time. They are a combination of seismogenic faults and gigantic collapses. This may be exemplified by the Shartla step (Solonenko 1973), where small fault scarps and grabens cut the surface of the piedmont debris cone on the flank of this step (Fig 17).
Some intermediate steps are destroyed by local pedimentation (Fig 13, 14). These steps are at a final evolutionary stage, and at their locations formation of piedmont plains begins.
The Zunduk intermediate step is the largest on the rift valley slope (Fig 15). It is located on the NW shore of the Maloye Morye strait. The step is no more than 3 km wide and over 20 km long, and is bounded by the diverging northeasterly faults of the Primorsky rift zone. In the place of virgation, the rift slope has a stepped structure. Upslope, the intermediate step is locally limited by the summit slope, but not by a system of fault facets. This indicates isolation of the intermediate steps in the place of conjugation of the fault scarp with the summit slope.
Fig 18 System of inclined blocks in the marginal part of a large step at the rift val ley s lope near the Slyudyanka river mouth. The blocks were formed later than the Neogene pediment shown by an arrow.
GeoJournal 23.3/1991 205
Fig 19 Northwestern shore of the Olkhon island near the Budun cape. Inclined blocks within the residual step are seen at left and centre. The inclined surface at right is an inversionally uplifted Neogene depression and a part of the Olkhon uplift. Landslides occur at the boundary between the residual step and the uplift.
_ _ _ _ _ _ _ _
The morphological features of the Zunduk step change along its strike. This phenomenon reflects evolution of this type of structural form on the rift valley slope. In the SW part of the rift, this step is located in a middle-mountain position (Fig 15), and is divided by transverse faults into several blocks. At the foot of its frontal scarp, an inclined piedmont plain is present. Both the Primorsky uplift and the intermediate step become lower toward the NE crossing the Zunduk transverse fault. Farther NE, the intermediate step is separated from uplift both by a fault scarp and by a wide, valley- like graben that becomes wider towards the NE. In this area, the frontal scarp of the intermediate step is below the level of the lake surface and is consequently strongly influenced by wave abrasion. The step becomes lower behind the next transverse fault located northeastward. This is a low massif bordered by active cliffs. The lake water has penetrated into small depressions behind the step (Fig 6). Changes in the intermediate step morphology indicate its evolution, from isolation on the rift valley slope to complete disappearance. This results in expansion of the rift valley and in rejuvenation of its slope within the zone of the long-living marginal fault. Such evolution of intermediate steps is a typical feature of rift zones with relict-horst (or "baikal") orogenesis (Florensov 1965).
Modern Tectonic Movements
Vertical movement data which are the result of repeated geodetic observations characterize modern geodynamics of the Baikal rift valley (Logatchev 1987; Kashin 1989). The Primorsky and Baikalsky ridges forming the W shoulder of the rift, are presently being uplifted. Rates of the modern uplift of the Primorsky ridge range from +0.9 to +11.2 mm/yr. Rate of modern uplift of the Baikalsky ridge is +8.8 mm/yr. The Zunduk step and the bottom of the rift valley subside with rate up to -5 .4 ram/yr. On the W Baikal coast there is accordance between the modern and recent tectonic movements. But the recent vertical tectonic movements have the rates calculated for the 25 mln years which are lesser in order than the rates of modern movements. The rates are +0.1 mm/yr for the Baikalsky ridge and -0 .2 mm/yr for the rift valley bottom. Common spectrum of modern vertical movements of the Earth's crust in the region has wave component with short period. This component was exposed on profiles with reiterative repeated geodetic observations (Logatchev 1987).
The S Baikal coast experiences modern uplift with a rate from +3.5 to +4.1 ram/yr. These data characterize the modern movements of the Earth's crust in domes and in blocks uplifts surrounding the rift valley. To the N of
Fig 20 Western Baikal shore near the Ledyanaya fiver mouth. Different evolutionary stages of rock badland on the rift valley slope. Traces of a large collapse obliterating fault facets (right).
206 GeoJournal 23.3/1991
the Selenga river delta and near the Bargusin river mouth the Baikal rift has modern subsidences with the rate - 1 . 6 mm/yr.
Significance of Listric Faults in the Rift Structure
In its extreme NE section the Zunduk step is inclined northwesterly, towards the Primorsky uplift. The same tectonic distortion is observed on the submarine horst in the North Baikal basin, which is a continuation of the intermediate step (Lamakin 1952). This indicates that the normal faults become listric faults at the final stage of the intermediate step evolution. As insufficient geophysical data are available, we cannot exactly appreciate the significance of listric faults in the morphotectonics of the Baikal rift valley. Not infrequently, actively uplifting inclined blocks, such as the Olkhon uplift (Fig 6, 7), are considered to be produced by movements along listric faults. In fact, their tectonic distortion results from other reasons. The Olkhon uplift and the active uplifts of the underwater Akademichesky ridge separate the individual basins of the Baikal rift valley (Fig 2, II, III) and are the rift shoulders striking along the deep South Baikal depression.
Geomorphic indicators of listric faults are quite different. Interrelations exist between tectonic distortions of blocks resulting from listric faulting and general subsidence of the blocks. This phenomenon is produced by varying amplitudes of block subsidence along the
faults limiting the intermediate steps. Such blocks or systems of blocks are observed on the rift valley slopes. They are not numerous. The inclined subsiding blocks, the marginal block of the Zunduk step included, occur near the N termination of Lake Baikal (Fig 18) where they are located within the marginal segment of the step between the Baikal ridge and the rift val ley. On the NW shore of the Olkhon island, where the residual step is abraded and split into separate blocks, the latter are inclined towards the mainland and limited by active cliffs (Fig 19). This indicates common subsidence of the blocks and flattening of faults with depth.
Discussion
The large dimensions of the Baikal rift valley, as compared with similar landforms in S East Siberia, should be explained. In our opinion, this phenomenon results from the Baikal rift valley being confined to the faults of the NE-SW striking global system. Rifts with the above or the NW-SE orientations are usually characterized by large dimensions (compare gigantic rifts of Red Sea, Aden Bay and Ethiopia with neighbouring East African rift valleys). At the margins of the Gondwana continents, great escarpments (Oilier 1984) maintain morphological youth if they strike NE-SW or NW-SE. We may assume that the above fault system is favourable for rifting due to planetary processes occurring on the Earth.
References
Florensov, N. A. : Mesozoic and Cenozoic depressions in Pribaikalye (near Baikal region). 258 p. Ac. Sci. Press. Moscow, 1960. (in Russian)
Florensov, N. A.: On the problem of mountain building mechanism in Inner Asia. Geotectonika (Geotectonics) 4, 3-14 (1965) (in Russian)
Florensov, N.A.: Rifts of the Baikal mountain region. Tectonophysics 8, 443-456 (1969)
Florensov, N.A. (ed.): Uplands of the Pribaikalye (near Baikal region) and Transbaikalye. Nauka, Moscow 1974.
Florensov, N.A.; Galkin V.I.: Active faults on the western shore of Lake Baikal. Izvestia Vostochno-Sibirskogo otdela Geograph. obstchestva SSSR 65, 73-83 (1967) Irkutsk (in Russian)
Goldyrev, G.S.: Sedimentation and the Quaternary history of the Lake Baikal basin. Nauka Press, Novosibirsk 1982 (in Russian)
Kashin, L.A. (ed.): Map of modern vertical movements of the Earth's crust of the USSR territory on geodetic data. Scale 1 : 5000000; 1989.
Lamakin, V.V.: Ushkany islands and the problem of the Baikal origin. Geografgiz, Moscow 1952.
Lamakin, V.V.: Obruchev fault in the Baikal basin. In: Voprosy geologii Azii (Problems of the geology of Asia) 2,448-478 Ac. Sci. Press, Moscow 1955. (in Russian)
Logatchev, N.A.; Florensov, N.A.: The Baikal system of rift valleys. Tectonophysics 45, 1-13 (1978)
Logatchev, N.A. (ed.): Processes of relief formation in Siberia. Nauka Press, Novosibirsk 1987.
Puzyrev, N.N. (ed.): The deep structure of Baikal indicated by seismic data. Nauka Press, Novosibirsk 1981. (in Russian)
Ollier, C.D.: Morphotectonics of continental margins with great escarpments. In: Tectonic Geomorphology, Proc. of the 5th Annual Binghampton Geomorphology Symposium, September 1984.
Solonenko, V.P.: Earthquakes and relief. Geomorphologia (Geomorphology) 4, 3-13 (1973) (in Russian).
Ufimtsev, G.F.: Neotectonics of the Baikal rift and inferences as to the structure. Int. Geol. Review 28, 8, 969-984 (1986)
Zorin, Y.A.: The Baikal rift: an example of the intrusion of asthenospheric material into the lithosphere as the cause of disruption of lithospheric plates. Tectonophysics 73, 91-104 (1981)
